Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2077477
AXLES PIERCING THRUST BEARING
FOR REFRIGERATION COMPRESSOR
The present invention relates generally to a
hermetic compressor and more particularly to small
refrigeration compressors used in household
appliances. An area of interest in the compressor
art is how to construct a more efficient and
quieter compressor. The efficiency of a
compressor is expressed as an energy efficiency
ratio (EER) which is measured by dividing the BTU
per hour output of the compressor by the power
consumption under standard running conditions.
The higher the EER the greater the efficiency.
One area that has received attention is that
of mechanical friction within the compressor. The
crankshaft of compressors generally rotates about
a vertical axis and therefore requires journalling
within a frame and bearings to position and
confine its rotation. A thrust bearing is used to
bear the weight of the crankshaft and motor parts.
In the past, these bearings have generally been of
a plain or oil film type, either having two
machined surfaces ru~bing together or one or two
hardened washers. Another type of bearing in use
is a ball bearing system. A disadvantage of ball
bearings is that they increase the noise of the
compressor and also increase the cost of the
compressor as well.
According to the present invention, it is
found that friction is reduced by the use of a
bearing pin pressed through the crankshaft sliding
upon the bearing hub of the compressor in a line
contact.
In the preferred embodiment of the invention,
a compressor having a rotating crankshaft within a
support frame or cylinder block includes an
elongated bearing or pin disposed within the
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crankshaft, that rotatably bears against the
support frame or cylinder block. The bearing pin
made out of hardened steel provides a line contact
against the bearing hub of the support thereby
reducing friction as compared to previous
compressor bearings.
In an alternative embodiment of the
invention, two hardened pins are rotatably
disposed within the crankshaft and maintain a line
contact with the support or cylinder block.
In another form of the invention, the
- hardened pin disposed through the crankshaft has
two sleeves or rollers, one on each side of the
crankshaft. These rollers allow a greater
opportunity for rolling movement between the pin
and bearing hub on the cylinder block.
A particular advantage of the compressor of
the present invention is that friction is
minimized by having the contact between the
bearing hub and bearing comprise a line contact
where the pin and bearing hub meet.
The invention, in one form thereof, provides
a refrigeration compressor for use in
refrigerators. The compressor includes a cylinder
block mounted within a housing and having a piston
reciprocatingly disposed within a cylinder. A
crankshaft means for reciprocating the piston in
the cylinder is provided that is journalled in a
vertical bore of the cylinder block and has an
upper end extending upwardly above a bearing hub.
The bearing hub has an upper end face defining the
vertical bore upon which an elongated bearing,
extending transversely through the crankshaft
means, is supported. A rotor is secured onto the
crankshaft concentric with a stator mounted in the
cylinder block.
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In one aspect of the previously described
form of the invention, the elongated bearing is a
one piece thrust pin disposed through and
perpendicular to the axis of the crankshaft means.
In this preferred embodiment, the thrust pin is a
hardened steel pin having a hardness of between 73
and 78 on the Rockwell hardness scale.
In accordance with an alternative embodiment
of the invention, the elongated bearing is a
thrust pin having two rotatable sleeves. The
sleeves rotate about opposite ends of the thrust
pin on opposite sides of the crankshaft. The
thrust pin is pressed through the crankshaft.
In accord with another embodiment of the
invention, the thrust bearing is comprised of a
plurality of elongate bearing pins rotatably
received within the crankshaft. These pins, which
rotate within the crankshaft, extend beyond the
crankshaft outer diameter creating a line contact
with the bearing hub upper end face surface.
According to a further aspect of the
invention, an oil lubrication means communicating
oil to the bearing from the oil sump. This oil
lubrication means comprises a spiral groove on the
crankshaft opening to the bearing and an oil
pumping means in communication with the spiral
groove for pumping oil from the oil sump through
the spiral groove to the bearing.
According to a further aspect of the
invention, the invention comprises a housing
having mounted therein a compressor unit having a
support frame. The support frame has a bore
surrounded by an end face. The compressing unit
has a crankshaft with an elongate bearing
extending through the crankshaft and supported by
the end face of the frame. The crankshaft is
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connected between the compressor unit and a motor
having a rotor and stator.
The above mentioned and other features and
objects of this invention, and the manner of
attaining them, will become more apparent and the
invention itself will be better understood by
reference to the following description of
embodiments of the invention taken in conjunction
with the accompanying drawings, wherein:
Fig. 1 is a longitudinal sectional view of a
compressor of the type to which the present
invention pertains;
- Fig. 2 is an enlarged fragmentary sectional
view of the compressor of Fig. 1 particularly
showing the bearing pin of the present invention;
Fig. 3 is a view of the present invention
taken along the line 3-3 of Fig. 1 and viewed in
the direction of the arrows;
Fig. 4 is an enlarged transverse sectional
view of an alternate embodiment of the bearing of
the present invention;
Fig. 5 is an enlarged fragmentary sectional
view of a further alternate embodiment of the
present invention.
Corresponding reference characters indicate
corresponding parts throughout the several views.
The exemplifications set out herein illustrate a
preferred embodiment of the invention, in one form
thereof, and such exemplifications are not to be
construed as limiting the scope of the invention
in any manner.
Referring now to Fig. 1, there is shown a
compressor having a housing generally designated
as 10. The housing has a top portion 12 and a
lower portion 14 that are hermetically secured
- together as by welding or brazing. A flange 16 is
20 774 77
welded to the bottom of housing 10 for mounting
the compressor.
Located inside the hermetically sealed
housing 10 is a motor generally designated at 20
having a stator 22 and rotor 24. The stator 22 is
provided with windings 26. Stator 22 is secured
to the support frame or cylinder block 38 by means
of screws. The rotor 2 4 has a central aperture 2 8
provided therein into which is secured crankshaft
30 by an interference fit. A hermetic terminal 32
is provided on bottom portion 14 of the compressor
for connect~ng motor 20 to a source of electrical
power. As shown in Fig. 1, a motor relay 34 is
connected over terminal cluster 32 and a terminal
shield 36 covers both terminal cluster 32 and
motor relay 34.
Within housing 10 is mounted 2 support frame
or cylinder block 38 resiliently suspended within
housing 10 by suitable spring mounts such as
compression spring 40 connected to cylinder block
38 and bottom portion 14 of compressor 10.
Although only one spring is shown, it is to be
understood that a number of springs are provided
at proper positions to support cylinder block 38
within housing 10.
Cylinder block 38 has a horizontally
extending cylinder bore 42 which is sealed off at
the end adjacent to housing 10 by cylinder head 44
including suction valve 46, dischzrge valve 48,
suction plenum 50 and discharge plenum 52.
Connected to cylinder head 44 is a suction muffler
54. A suction tube 55 permits refrigerant to
enter compressor from a refrigerant system (not
shown). Discharge plenum 52 is in communication
with a discharge tube (not shown) leading out of
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housing 10. From the center of cylinder block 44
extending upwardly is a bearing hub 56 defining a
vertical bearing bore 58. Bearing hub 56 has an
end face 60 facing upwardly on bearing hub 56.
Crankshaft 30 is journalled for rotation
within vertical bearing bore 58. As shown in Fig.
1, and in accordance with the present invention,
an elongate bearing 62, such as a pin, extends
transversely through the crankshaft 30. If
desired, bearing pin 62 can be press fit in
crankshaft 30. Bearing 62 rides upon endface 60
of bearing hub 56. A connecting rod 64 is
attached to the end of crankshaft 30 that extends
through bearing bore 58. Connecting rod 64 is
attached to piston pin 66 that fits within
cylinder bore 42, and causes piston 66a to
reciprocate within cylinder bore 42 as crankshaft
30 rotates.
The reciprocating compressor described herein
provides a lubrication system for lubricating the
components of the compressor including the
crankshaft 30 and bearing 62. An oil pickup tube
68 is disposed within crankshaft 30 and is in
communication with spiral groove 70 extending
around the outer surface 72 of crankshaft 30. Oil
pickup tube 68 is partially immersed in an oil
sump 71. Spiral groove 70 is in communication
with a radial oil passage 74 (see Fig. 1). Radial
oil passage 74 allows oil to travel to groove 70
and through groove 70 to bearing pin 62.
Fig. 2 shows bearing pin 62 disposed within
crankshaft 30 resting upon endface 60 of bearing
hub 56. Bearing 62 is preferably made from a
steel pin hardened to a value of between 73 and 78
on the Rockwell hardness scale. Preferably pin 62
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is smoothed and polished before being press fit
into hole 78 in crankshaft 30.
In operation, the bearing pin 62 forms a line
contact with endface 60. This line contact of
minimal bearing area increases the efficiency of
the compressor. Also during operation, oil pickup
tube 68 will provide a flow of oil through radial
oil passage 74 and through spiral groove 70 into
communication with bearing pin 62 and end face 64,
thereby reducing friction even further.
Fig. 4 shows an alternate embodiment of the
present invention where bearing 62 is composed of
two hardened steel pins 62' and 62" rotatably
disposed within hole 78 in crankshaft 30. In this
embodiment, a line contact is formed between pins
62' and 62" and endface 60 just as in the
preferred embodiment. In this embodiment, the two
pins extend out of the crankshaft and are held in
place by an inner face 80 of rotor 24.
Fig. 5 shows another alternate embodiment
of the invention where bearing 62 comprises a pin
82 inserted within hole 78 of crankshaft 30. Pin
82 has sleeves 84' and 84" rotatably disposed on
opposite sides of pin 82 extending through
crankshaft 30. Sleeves 84' and 84" create the
line contact upon which crankshaft 30 bears
against endface 60. Sleeves 84' and 84" and pin
82 are hardened to a value of between 73 and 78 on
the Rockwell hardness scale.
It will be appreciated that the foregoing
description of various embodiments of the
invention is presented by way of illustration only
and not by way of any limitation and that various
alternatives and modifications may be made to the
illustrated embodiments without departing from the
spirit and scope of the invention.
B
